Tarantulas

Scientific Name: Family Theraphosidae

Description: Tarantulas are large, long-lived arachnids that have become popular to keep in captivity. When threatened, a tarantula exposes its fangs and puts its weight on its hind legs. If that does not deter a predator, the spider may use their legs to shoot urticating hairs toward their attacker. These are small barbed hairs that cause minor irritation in humans, but can kill small mammals.

Size: Adult tarantulas average five inches long. When spread out, their leg span is up to 11 inches. The Goliath bird-eating spider may be the world’s largest spider by weight—over 6 ounces!

Diet: While they pose few threats to humans, they are fierce predators of insects, and some South American species even hunt birds and small mammals. When tarantulas are ready for a meal, they grab their prey and inject it with immobilizing venom. The spider then kills the prey with its fangs and secretes digestive enzymes so that their meal can be slurped into their mouth. Tarantula venom may paralyze an insect, but it isn’t nearly toxic enough to pose a threat to humans.

Typical Lifespan: Wild tarantulas can live up to 30 years. The lifespan of the male tarantula is many times shorter than that of the female.

Habitat: Tarantulas are burrowing species. Most people only come across them when males wander about looking for a female to mate with.

Range: In the United States, wild tarantulas are only found in the southwest. They are more common in Mexico and Central and South America. Australia, Southern Asia, and Africa (excluding the Sahara Desert) also host populations of tarantulas.

Life History and Reproduction: Male tarantulas spin webs to signal females. The males leave sperm on the web, which the female spins into a cocoon with her eggs. If the male sticks around the web for too long, the female may eat him! Few animals prey on tarantulas, but the notable parasitic pepsis wasp disposes of tarantulas in a cruel way. When a pregnant wasp comes across a tarantula, she lays eggs on the body of the unsuspecting arachnid. When the eggs hatch, the wasp larvae eat the tarantula alive.

Fun Fact: Tarantulas spin webs for mating purposes rather than to capture prey.

Conservation Status: Certain species are affected by habitat destruction or the pet trade. Regulations are in place to prevent importation of tarantulas into the U.S., but there are few measures to prohibit the overcollection of tarantulas.